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Analysis of Handoff techniques used for hybrid networks: cellular/WLAN


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Most real life networks are hybrid networks. A hybrid network combines the best features of two or more networks. In networking terminology, a hybrid network according to “Information Technology control and Audit” are reliable and versatile. They provide large numbers of connections and data transmission paths to users. These hybrid networks may be treated as network nodes for analysis purpose. The two radio access technologies (RATs) are considered with cellular/WLAN depending on whether it is voice/ data, video. For observing practical result, some setups are required in laboratory which includes interface from personal computer to mobile terminal and vice-versa. The network simulator (Ns-2) is used for analysis purpose. The results shows the parameters like energy good put, Bandwidth utilization, packet delivery ratio, energy good put and energy consumed are improved after using hybrid networks.

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Analysis of Handoff techniques used for hybrid networks: cellular/WLAN

  1. 1. International Journal of Research in Computer ScienceeISSN 2249-8265 Volume 2 Issue 4 (2012) pp., A Unit of White Globe Publicationsdoi: 10.7815/ijorcs.24.2012.039 ANALYSIS OF HANDOFF TECHNIQUES USED FOR HYBRID NETWORKS: CELLULAR / WLAN Dr.P.B.Mane1, Viddhulata Mohite2 1 Principal, AISSC College of Technology, Pune, INDIA 2 Research Scholar, Bharati Vidyapeeth University College of Engineering, Pune, INDIA Email: viddhulata.mohite@gmail.comAbstract: Most real life networks are hybrid networks. of wireless networks. It is widely accepted that nextA hybrid network combines the best features of two or generation wireless networks will be heterogeneous inmore networks. In networking terminology, a hybrid nature with multiple wireless access according to “Information Technology While heterogeneity poses new challenges to achievecontrol and Audit” are reliable and versatile. They interpretability among different wireless networks,provide large numbers of connections and data their complementary characteristics can be exploitedtransmission paths to users. These hybrid networks with the interworking to enhance service provisioning.may be treated as network nodes for analysis purpose.The two radio access technologies (RATs) areconsidered with cellular/WLAN depending on whetherit is voice/ data, video. For observing practical result,some setups are required in laboratory which includesinterface from personal computer to mobile terminaland vice-versa. The network simulator (Ns-2) is usedfor analysis purpose. The results shows the parameterslike energy good put, Bandwidth utilization, packetdelivery ratio, energy good put and energy consumedare improved after using hybrid networks.Keywords: Radio Resource Management (RRM), Figure 1: Scenario of heterogeneous wireless networksRadio Access Technologies (RAT), Vertical Handoff, The popular cellular networks and wireless LocalHeterogeneous Network. Area Networks (WLANs) are two most promising technologies, and the cellular/WLAN interworking has I. INTRODUCTION attracted much research attention from both the The most real life networks are hybrid networks. industry and academia. Network protocol: AODV,Theese hybrid networks may be treated as network Number of nodes: 20 Data transfer protocol: TCPnodes for analysis purpose. The two Radio Access MAC layer standard: IEEE 802.11 are used to designTechnologies (RATs) are considered with cellular network./WLAN. To design and develop algorithm for practical Cellular networks are originally designed to provideresults needs interface between personal computer and high quality voice service with wide area terminal. Social network-based systems usually The first generation (1G) cellular networks aresuffer from two major limitations: upgraded to the second generation (2G) with digital 1. They tend to rely on a single data source (e.g. email technologies. The 2G systems e.g. the global system traffic) for mobile communication (GSM) are further extended 2. The form of network patterns is often privileged with packet switching for more efficient data over their content. transmission. For example, the data transmission rate is increased from 9.6 kbps with GSM to around 100 To go beyond these limitations we describe a kbps with the General Packet Radio Service (GPRS).system we developed to visualize and navigate hybrid Currently the third generation (3G) augmented withnetworks constructed from multiple data sources with multimedia service support has been commercialized,a direct link between formal representations and the such as the Universal Mobile Telecommunicationraw content. Motivated by ever increasing demand for System (UMTS) and cdma 2000 c1 [1]. The UMTSwireless communication services, the past decade has system supports a data rate up to 2 mbps with greaterwitnessed rapid evolution and successful deployment capacity and improved spectrum efficiency. However,
  2. 2. 46 Dr.P.B.Mane, Viddhulata Mohitethe deployment cost remains high due to expensive allocation. Also, the unique characteristics of theradio spectrum and implementation complexity. On the integrated network should be taken in to account.other hand, WLANs have also achieved great successand provide higher data rates at a much higher data III. METHDOLOGYrates and much lower cost. However, designed as awireless extension to the wired Ethernet, a WLAN can Our objective is to evaluate if this approach canonly cover a small geographic area. For instance, an yield capacity benefits over that of the original cellular802.11b access point (AP) can communicate with network. While the use of the relays to form a hybridmobile within up to 60 meter at 11 Mbps and upto 100 network provides shorter higher rate communicationmeter at 2Mbps with unidirectional antennas. The links, multichip forwarding contributes to a reductionstandardization for 3G/WLAN interworking is now in in capacity [3]. We determine under what conditionsprogress by the third generation partnerships project and by how much is the downlink capacity of a hybrid(3GPP) and the third generation partnership project 2 cellular ad-hoc network higher or lower than that of(3GPP2) from a cellular network operator’s the original pure cellular network. The capacity of aperspective [2]. Six interworking scenarios are defined cellular data networks can be improved by creating ain 3GPP TR 22.934 to implement the 3GPP/WLAN larger number of smaller cells, each of which housesinterworking step by step. The interworking an expensive base-station (BS). The benefit of such anrequirements, architecture and procedures have been approach is the increased spatial reuse of the spectrum.specified in 3 GPP TR 23.234. Nonetheless, the Alternatively, in order to increase spatial reuse,specification on quality of service (QoS) provisioning cellular networks may be augmented with ad-hocis still limited to very high level discussion, such as wireless connectivity; this is attractive as compared to3GPP TR 23.836. The remaining paper includes the former approach in terms of the incurred cost.handoff algorithms for quality of service provisioning Mobility management consists of two aspects i ein section II. Section III follows methodology used, location management and handoff management.whereas section IV gives results. Section V and section Location management continuously tracks theVI are conclusion and references respectively. mobile’s location, while handoff management maintains ongoing connections when switching attachment points. Generally, the handoff process isII. PHANDOFF ALGORITHMS FOR QUALITY OF divided into three stages i.e. initiation, decision, SERVICE PRO-VISIONING execution [4]. It is known that mobile wireless network exhibitsome features distinct from wired networks. First, a Depending on the decision entities, there arewireless channel becomes time-varying and location- mobile-controlled handoff, mobile-assisted handoffdependent due to radio propagation characteristics. and network-controlled handoff. Horizontal handoffThe achievable channel capacity may be substantially within a homogeneous wireless network is inherentlydegraded by impairments such as large-scale path loss supported as a functionality of the mobilityand small-scale fading resulting from multipath time management. In the 3G cellular network UMTS; theredelay spread and Doppler frequency dispersion. To is GPRS Mobility Management (GMM) for the linkimprove channel capacity, frequency reuse is enabled layer and network layer mobility [5]. Tunnelingin cellular networks. In cellular networks is further protocols are used in the cellular core to supportcomplicated by co-channel interference and user roaming. In CDMA 2000 system, mobile IP ismobility. Resource allocation plays a key role in introduced to provide network layer transparency toeffectively provisioning QoS guarantee and efficiently IP-based applications (IP mobility) under the sameutilizing the scare radio resources. There has been packet serving node (PDSN) and between differentextensive research on resource allocation for PDSNs. In contrast, current UMTS specifications onlyheterogeneous wireless networks: which involves support IP mobility under the same GGSN node. Invarious aspects from the packet level to call level, such three state evolution specified, mobile IP is beingas packet scheduling and medium access control considered for inter UMTS or inter-technology IP(MAC), flow and congestion control, QoS routing, and mobility. The mobility management in WLANs iscall admission control (CAC). In the cellular/WLAN much simplex since they are designed for local areas.integrated network, resource allocation becomes much In 802.11 a distribution system ( 802.3- typemore challenging due to network heterogeneity. The Ethernet) connects multiple basic service sets (BSSs)resource allocation techniques need to be adapted to into an extended service set (ESS). On the other hand,this heterogeneous networking environment and vertical handoff in heterogeneous wireless networksaddress many emerging new problems. To achieve a need to address many new challenges posed byhigh utilization efficiency, the resources in the network heterogeneity. In a loosely coupledintegrated systems should be jointly considered in the cellular/WLAN network, the vertical handoff can be mobile-assisted or mobile-controlled, while tight coupling offers mobile-assisted or network-controlled
  3. 3. Analysis of Handoff Techniques used for Hybrid Networks: Cellular / WLAN 47 results in an overlay structure, which offers both cellular access and WLAN access to dual mode mobiles in WLAN covered areas. In hierarchical cellular networks small-sized microcells are overlaid with large macrocells. However, the cellular network and WLANs differ intrinsically in the physical layer, medium access and link control layers. It is necessary to differentiate the downward vertical handoff from a cell to a WLAN and upward vertical handoff from a WLAN to a cell. Further vertical handoff may originate from quality of service (QoS) enhancement or load balancing considerations other than maintaining connectivity [7]. Hence, not only can vertical handoff proceed when a mobile moves out of the cell/WLAN border but also back-and-forth vertical handoff can take place when mobile moves within the cell/WLAN. Vertical handoff algorithms need to decide whether and when to perform a handoff to minimize the unnecessary handoff and the impact of ping-pong effect and where to direct the handoff in case of multiple access interfaces. Many works on the vertical handoff decision are based on metrics such as RSS, SNR and user moving speed. Due to network heterogeneity, such traditional metrics in the two networks are rather disparate and should be used in a way different from that for horizontal handoff. The transport layer scheme proposed to supports UMTS and WLAN vertical handoff via stream control transmission protocol (SCTP). IV. RESULTS Figure 2: Sequence diagram of Handoff Agent used AODV with following specifications:vertical handoff with enhanced performance but highcomplexity. In order to make an intelligent handoff Packet size:1000 #in octetsdecision, timely information must be retrieved from Capacity: 5e6 # 4.7e6candidate networks. Traditionally metrics measured Reserved Bandwidth: 0.1e6include received signal strength (RSS), signal –to- Grad step: 0.05noise ratio(SNR) or bit error rate (BER), Packet loss Rate Control:1rate etc [6]. In the heterogeneous cellular/WLAN Queue is Drop Tail with length 50interworking environment the information collection Antenna unidirectionalbecomes much more challenging. Especially, the loose Number of nodes: 21coupling may result in a large overhead and longlatency for the information exchange between the twonetworks. The networks information is collected frommobiles via power control and link adaptationsignaling and is managed with local databases. Thedata can be retrieved from the database upon requestand transferred to the mobile through extended cellbroadcast or in-band signaling in a piggy back fashion.The mobiles dual network interfaces are alwaysenabled active for control messages. In this way, themobile keeps receiving periodic advertisements fromboth networks indicating network conditions such aslink performance, channel utilization and traffic load.Handoff decision algorithms while the cellularnetwork provides ubiquitous connectivity with widearea coverage, WLAN s are only deployed disjoint in Figure 3: The terminal windowhotspot areas. The cellular/WLAN interworking then
  4. 4. 48 Dr.P.B.Mane, Viddhulata Mohite Figure 4: Animator window Figure 7: CBP Figure 5: Final output Figure 8: Nodes vs energy consumed Figure 6: Intermediate execution state Figure 9: Nodes vs. energy-Good put
  5. 5. Analysis of Handoff Techniques used for Hybrid Networks: Cellular / WLAN 49 Figure 10: Bandwidth utilization Figure 13: CDP Figure 11: Packet Delivery Ratio Figure 14: Energy consumed V. CONCLUSION From the graphs, it is clear that the performance features like, CDP, CBP, Bandwidth utilization, energy good put, energy consumed, Packet delivery ratio is better for the hybrid network. Hence it can be concluded that as compared to the original system of network, the developed hybrid network which uses AODV for handoff is better. Handoff algorithm is an important aspect for the integrated system of cellular networks and WLANs. So we can apply a handoff algorithm scheme for the cellular/WLAN integrated network to support multiple service classes. Figure 12: Energy-good put
  6. 6. 50 Dr.P.B.Mane, Viddhulata Mohite VI. FUTURE WORK The method implemented above for verticalhandoff in heterogeneous network shows all abovementioned parameters are improved. But this is onlyimplementation of handoff by Core Network (CN).The remaining condition initiated by Mobile Terminal(MT) due to new call indication or due to new RadioAccess Technology (RATs) or due to low battery ordue to low Radio Signal Strength (RSS) is future work.The same analysis can be done for all above conditionby using Network Simulator (Ns-2) as future part. VII. REFERENCES[1] “Radio Resource Management in further Wireless Networks: Requirement and Limitations.” By Jens Zander, Royal Institute of Technology.[2] “An Efficient Radio Resource allocation scheme for spatial Multi-user Access in MIMO/OFDM Systems” By Ying Jun Zhang, Kaled Ben Lettering IEEE Transactions on communications, Vol.53, NO.1, January 2005. doi:10.1109/TCOMM.2004.840666[3] “Resource allocation for multicast services in multicarrier wireless communications” by Changho Suh, Jeoghoon Mo.IEEE Transactions on wireless communication.vol.7, NO.1, January 2008. doi:10.1109/TWC.2008.060467[4] “Resource Management for Service Provider in Heterogeneous Wireless Network” By Xu Yang, John Bigham, Laurie Cuthbert.[5] “Intelligent Radio Resource Management for IEEE 802.11 WLAN” By, l.g.cuthbert, j.bigham.[6] “ An Algorithm For Radio Resource Management in Integrated Cellular/WLAN Networks” By Ioannis Modeas,Alexenderos Kaloxylos,Nikos Passas,Lazaros Merakos in Annual IEEE International Symposium On Personal ,Indoor and Mobile Radio Communications(PIMRC 07).[7] “Resource allocation for Delay Differentiated traffic in multi-user OFDM systems” By Meixio Tao,Ying – Chang, Liang, and Fan Zharg.In IEEE Transactions on wireless communications Vol.7,No.6,June 2008.[8] IEEE Transaction on Vehicular Technology, vol.57, no.4, July 2008 “Analysis of common radio resource management scheme for end-to-end QOS support in multiservise heterogeneous wireless networks” Abdul Hasib and Abraham O.Fapojuwo, senior member, IEEE. doi:10.1109/TVT.2007.912326 How to cite Dr. P.B. Mane, Viddhulata Mohite, "Analysis of Handoff Techniques used for Hybrid Networks: Cellular / WLAN". International Journal of Research in Computer Science, 2 (4): pp. 45-50, July 2012. doi:10.7815/ijorcs.24.2012.039